i know this problem
here is the simple way of explaining it
each member that connects uses more of your internet connection and it also depends on your speed and range
the end of stream means that your internet can not keep up and the server is running of a cmd program that is the main command center of all computers , that doesnt get enough info from your computer so it tells the server to disconnect you and bring up that message
and the java error is due to modding minecraft or a minecraft that isnt the same version of the server so the programming will not match the minecraft programming
youl need to reupdate minecraft and atleast get a faster router , wireless card , or dongle if you dont you will keep getting these errors